While Brazil may indeed be the spiritual birthplace of mixed martial arts, the combat sport is hardly the national pastime.

That honor belongs to soccer, a sport in which Brazil has won more world championships (five) than any other nation.

But while Brazilians specialize in playing a version of soccer known as "the beautiful game," off-pitch clashes between fans can sometimes turn violent. So with many of the nation's soccer clubs now supporting UFC athletes, is the promotion asking for trouble?